The present invention relates to shock mounts and in particular to shock mounts for tuning fork crystals.
Oscillator stability is an extremely important factor in total fuzing accuracy for time fuzes used in artillery shells. For a 200-second fuze with 0.1-second maximum time error over the operating temperature range, the oscillator must remain within .+-.0.05 percent of its nominal setting. Crystal oscillators exhibit this sort of high stability.
Therefore it is desirable to use crystal oscillator circuits in projectile fuzes in lieu of less stable, more expensive, and bulkier frequency generators.
Although most common shapes of high frequency crystals can be made gun-rugged, those crystals require exceptional amounts of current for proper operation. For low oscillation frequency capability, a tuning fork type of crystal is often the best choice.
In the past, crystals of the tuning fork variety have been shown not to be reliable in their ability to survive high-g shocks. For such a crystal to be practical for projectile fuze applications, it must be capable of sustaining shock in the 20,000 to 30,000 g range with virtually 100 percent survival. Heretofore an integral shock mount in the crystal assembly was required to perform the entire shock attenuation function.